GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

If the sunroof is experiencing an intermittent inoperative condition, check the sunroof switch ground circuit for an open. If the sunroof switch ground circuit is open, the switch may take a redundant path to ground through the switch illumination circuit. When the lights are turned On, the redundant path to ground is removed. The sunroof may become inoperative.

A short to voltage in any one of the sunroof switch signal circuits will most likely open the switch.

By performing sunroof control module circuit tests at the inline harness connectors behind the right rear sail panel, may prevent the removal of the headliner.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests the integrity of the ground circuit of the sunroof switch. If the switch illuminates when the headlamps are turned ON, the switch ground circuit is OK. Also, turning on the headlamps eliminates the possibility of the switch finding an alternative path to ground through the illumination circuit.

  2. This step tests the integrity sunroof switch, if the roof operates when performing this test, the switch is at fault. If the fuse in the jumper wire opens when you perform this test, a short to battery voltage may have occurred.

  3. This step tests for voltage in the battery positive voltage circuit at the inline connector.

  4. This step tests the integrity of the sunroof enable signal circuit. If the fuse in the jumper wire opens when you perform this test, a short to battery voltage may have occurred.

Step

Action

Values

Yes

No

Schematic Reference: Sunroof Schematics

Connector End View Reference: Sunroof Connector End Views

DEFINITION: All functions of the power sunroof system are inoperative.

1

Have you conducted diagnostic system check- vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Attempt to operate the power sunroof through its full range of functions in order to verify that the power sunroof inoperative fault is present.

Does the Power Sunroof System operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the sunroof switch illumination.
  3. Turn ON the headlamps.

Does the sunroof switch illuminate?

--

Go to Step 4

Go to Step 8

4

  1. Turn OFF the ignition.
  2. Disconnect the sunroof switch.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a 3-amp fused jumper wire between any one of the roof or vent switch signal circuits and the ground circuit of the switch harness connector.

Did the sunroof move in the direction as tested?

--

Go to Step 12

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Remove the right rear sail panel to access the inline harness connector C310.
  3. At the inline harness connector, measure the voltage from the battery positive voltage circuit of sunroof control module to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 6

Go to Step 17

6

At the inline harness connector C310, measure the voltage between the battery positive voltage circuit of the sunroof module and the ground circuit of the sunroof module.

Does the voltage measure near the specified value?

B+

Go to Step 7

Go to Step 18

7

  1. Connect a 3-amp fused jumper wire from the sunroof enable signal circuit of the inline harness connector to a good ground.
  2. Press the appropriate sunroof switch.

Did the sunroof move in the intended direction?

--

Go to Step 11

Go to Step 10

8

Test the illumination circuit of the sunroof switch for an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 22

Go to Step 9

9

Test the ground circuit of the sunroof switch for an open. Refer to Circuit Testing and Wiring Repairs .

Do you find and correct the condition?

--

Go to Step 22

Go to Step 14

10

Test the sunroof enable signal circuit between the inline harness connector C310 and the sunroof control module for an open. Refer to Circuit Testing and Wiring Repairs .

Do you find and correct the condition?

--

Go to Step 22

Go to Step 13

11

Test the sunroof enable signal circuit between the sunroof control module and the rear integration module for a short to battery voltage or an open. Refer to Circuit Testing and Wiring Repairs .

Do you find and correct the condition?

--

Go to Step 22

Go to Step 16

12

Test all of the sunroof switch signal and express circuits for a short to battery voltage. Refer to Circuit Testing and Wiring Repairs .

Do you find and correct the condition?

--

Go to Step 22

Go to Step 14

13

Test the battery positive voltage circuit and the ground circuit between the sunroof control module and the inline harness connector C310 for an open. Refer to Circuit Testing and Wiring Repairs .

Do you find and correct the condition?

--

Go to Step 22

Go to Step 15

14

Inspect for poor connections at the harness connector of the sunroof switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Do you find and correct the condition?

--

Go to Step 22

Go to Step 19

15

Inspect for poor connections at the harness connectors of the sunroof control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Do you find and correct the condition?

--

Go to Step 22

Go to Step 20

16

Check for poor connections at the harness connector of the rear integration module (RIM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Do you find and correct the condition?

--

Go to Step 22

Go to Step 21

17

Repair the short to ground or open in the battery positive circuit of the sunroof control module. Refer to Wiring Repairs and Connector Repairs .

Is the trouble corrected?

--

Go to Step 22

--

18

Repair the open in the ground circuit of the sunroof control module. Refer to Wiring Repairs and Connector Repairs .

Is the trouble corrected?

--

Go to Step 22

--

19

Replace the sunroof switch. Refer to Sunroof Switch Replacement .

Have you finished the replacement?

--

Go to Step 22

--

20

Replace the sunroof control module. Refer to Control Module References to replace, set and program.

Have you finished the replacement?

--

Go to Step 22

--

21

Replace the RIM. Refer to Control Module References to replace, set and program.

Have you finished the replacement?

--

Go to Step 22

--

22

Operate the system to verify the repair.

Do you find and correct the condition?

--

System OK

Go to Step 2